The present invention relates to a cylinder head of an engine, and more particularly, to a middle deck of a cylinder head that is adapted to efficiently cool engine oil.
In general, a water jacket is formed at a lower portion and an upper side of a middle deck of a cylinder head. The water jacket formed at a lower portion is used for cooling off an upper part of an engine""s combustion chambers. The water jacket formed at the upper side is used for cooling lubrication oil and a cam shaft and suction/exhaust valves, thereby letting hot engine oil flow, cool down lubrication oil and drain into an oil pan. Cooling is performed by a heat-exchange process.
Generally, a cylinder head is divided between upper and lower portions by a middle deck. Engine oil used to lubricate the camshaft and valves flows through the upper portion, while a water jacket is provided below the middle deck to act as a heat-exchanger. Various holes are formed through the middle deck for receiving spark plugs, etc.
The water jacket is normally located mostly on an exhaust side of the cylinder head as the exhaust side operates at a highter temperature, and, therefore, requires more cooling. The middle deck is generally a sloped planar surface, sloping down from the exhaust side of the cylinder head to an intake side.
However, the conventional structure of the middle deck (M) has drawbacks, as engine oil does not remain at the exhaust side long enough to effectively cool the engine oil as it flows down the sloped surface of the middle deck (M) downward toward the intake side.
The present invention provides a middle deck of a cylinder head that reduces the temperature of engine oil by heat-exchanging the engine oil flowing at the middle deck with cooling water flowing along a water jacket under the middle deck.
In accordance with an embodiment of the present invention, a partition is coupled to the the middle deck between an intake and exhaust side of a cylinder head. In addition, a plurality of radiating protruders are formed on the surface of the middle deck for enlarging the heat exchange contact area above the middle deck.
According to a further preferred embodiment of the invention there is provided a cylinder head with an exhaust side and an intake side opposite the exhaust side. The cylinder head also includes a middle deck separating a lower portion from an upper portion of the cylinder head. The middle deck is sloped from the exhaust side to the intake side. At least one partition is coupled to the middle deck in the upper portion. The at least one partition at least partially seperates the upper portion between the exhaust side and the intake side. The cylinder head also preferably includes at least one radiating protruder coupled to the middle deck in the upper portion. The radiating protruder is configured to increase a heat exchange surface area in the upper portion. In a preferred embodiment, radiating protruders are provided on both the exhaust and intake sides. These radiating protruders preferably have different shapes. Also, at least one boss extends through the middle deck for receiving a spark plug. A water jacket is disposed in the lower portion, preferably on the exhaust side. A portion without any partitions is located between at least two partitions, such as between two middle bosses for receiving spark plugs.